Nonlinear Color Mixing Correction in LCD Displays
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Solution Overview
Problem
Color liquid crystal displays suffer from nonlinear color mixing errors due to the gamma characteristic and additive failure, leading to chromaticity shifts in white and primary color ramps, which existing gamma correction circuits are unable to fully address.
Innovation Solution
A method and device utilizing a matrix color mixing model with virtual primary colors to analyze and correct color signal values, establishing material characteristic functions to adjust control signal values for accurate color display, incorporating a characteristic analyzing module, target synthesis module, and correction application module to perform video color conversion and correct nonlinear color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear additive three-color mixing model is used for color display, then the color mixing is simple and follows theoretical expectations, but nonlinear color mixing errors occur in actual LCD displays due to gamma characteristics and additive failure
Solution Approach 1:
The patent transforms the color mixing model from a simple linear additive model to a nonlinear model that incorporates gamma characteristics and additive failure compensation. By changing the mathematical parameters and relationships in the color mixing equations, the system achieves accurate color reproduction that matches actual LCD behavior while maintaining computational efficiency through pre-calibrated transformation matrices.
2Reliability
If gamma correction is applied to linearize the relation between control signals and color signals, then the nonlinear gamma characteristic is corrected, but additive failure and crosstalk effects remain causing chromaticity shifts
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and embedding compensation factors for additive failure and crosstalk effects directly into the color transformation matrices. Before actual color conversion occurs, the system incorporates correction terms that counteract the anticipated nonlinearities and interaction effects, thereby preventing chromaticity shifts rather than attempting to correct them afterward.
Solution Approach 2:
The patent introduces an intermediary color space transformation step that acts as a mediator between the input control signals and the final display colors. This intermediate transformation layer applies both gamma linearization and additive failure compensation simultaneously through a unified matrix operation, decoupling the complex nonlinear relationships into manageable sequential transformations.
3Device complexity
If traditional gamma correction circuits are used, then the implementation is simple, but they cannot fully address additive failure and crosstalk causing unstable primary colors and white point shifts
Solution Approach 1:
The patent merges multiple correction functions (gamma linearization, additive failure compensation, and crosstalk correction) into a single unified color transformation matrix operation. By combining these previously separate correction steps into one integrated matrix multiplication, the system achieves comprehensive color accuracy without requiring multiple separate correction circuits, thereby maintaining implementation simplicity while dramatically improving color stability.
Data Source
AI summary
The present invention discloses a method and an apparatus for correcting color mixing errors, which lets a color display device adopt a virtual material quantity concept and use at least one set of predetermined virtual primary colors to analyze mixed color signal values displayed on the color display device and establish a corresponding material characteristic functions between color control signal values and corresponding virtual control signal values, and eventually establish nonlinear color correction functions between a series of known control signal values corresponding to desired color signal values of the color display device, in such a way that when the color display device performs a video color conversion, the control signal values actually entered into the color display device are corrected to the corresponding target control signal values for allowing the color display device to display desired color signal values.